+ (print (message-text msg))))
+ (print "* MESSAGE DELIVERED (local)")
+ #t)
+
+
+;; Remote delivery
+
+(define (get-domain-from-email email-string)
+ (car (string-split (cadr (string-split email-string "@")) ">")))
+
+;; This is a hack - there's no built-in interface to res_query()
+;; in chicken, so we have to resort to a system call to dig...
+(define (get-mail-server-for-domain domain)
+ (let* ((mx-lines (let-values (((in out id) (process (conc "dig " domain " mx +short"))))
+ (with-input-from-port in read-lines)))
+ (mx-entries (map (lambda (l)
+ (let ((s (string-split l)))
+ (list (string->number (car s))
+ (string-drop-right (cadr s) 1)))) ; remove trailing "."
+ mx-lines))
+ (sorted-mx-entries (sort mx-entries (lambda (e f) (< (car e) (car f))))))
+ (if (null? sorted-mx-entries)
+ domain ; fall-back to email address domain if no mx entries
+ (cadar sorted-mx-entries)))) ; otherwise pick the highest priority server
+
+(define (deliver-message-remote msg config)
+ (let* ((domain (get-domain-from-email (message-to msg)))
+ (mail-server (get-mail-server-for-domain domain)))
+ (print "Attempting delivery to " mail-server)
+ (let-values (((tcp-in tcp-out) (tcp-connect mail-server 25)))
+ (let ((smtp-session (make-outgoing-smtp-session tcp-in tcp-out)))
+ (let ((result (and
+ (smtp-session 'expect "220")
+ (smtp-session 'send "helo " (config-host config))
+ (smtp-session 'expect "250")
+ (smtp-session 'send "mail from:" (message-from msg))
+ (smtp-session 'expect "250")
+ (smtp-session 'send "rcpt to:" (message-to msg))
+ (smtp-session 'expect "250")
+ (smtp-session 'send "data")
+ (smtp-session 'expect "354")
+ (smtp-session 'send (message-text msg))
+ (smtp-session 'send ".")
+ (smtp-session 'expect "250")
+ (smtp-session 'send "quit"))))
+ (close-input-port tcp-in)
+ (close-output-port tcp-out)
+ (print "Connection closed.")
+ (if result
+ (print "* MESSAGE DELIVERED (remote)")
+ (print "* REMOTE DELIVERY FAILED (unexpected server response)"))
+ result)))))